224 The Plant Formations of the High Mountains. 
3. Dry Mountains (South Island). 
"Commencing with one of the most xerophytic SIALONS; much-weathered 
greywacke, standing out from alpine shingle-slips in the North-eastern district 
(1200 m and upwards), the dominant plant is a black fruticose lichen. _Pressed 
as closely to the rock as possible will be numerous, hard, circular greyish 
cushions of Raoulia dryoides, the largest some 30 cm in diam. and ı7 cm deep. 
Here too will be the remarkable Helichrysum coralloides, an open shrub some 
40 cm high, if sheltered‘), but a true cushion, if fully exposed; its shoots cylin- 
'drical, 8 mm in diam. and the small, glossy hie leaves looking like tuber- 
cles, the spaces between being packed with white wool?). ZZ. Selago agg. and 
H. microphyllum are also plants of this association, but the three are rarely 
present at the same time, Other plants are: — Aymenanthera dentata var. 
alpina, its rigid, semi-spinous, leafless, stout stems forming open divaricating 
cushions; Veronica decumbens or V. pinguifolia pressed close to the crevice; 
Pimelea Traversit, small loose cushions of Colodanthus acicularıs, the fine white- 
flowered Myosotis saxatilis, the rosettes of Eptlobium crassum and possibly broad 
flattened sheets’ of Bodpeippnig nivalis. H.coralloides is confined to the North- 
eastern district, but dry alpine rocks in many parts of the Eastern and North 
Otago districts bear a closely allied association °). 
 Equally xerophytic is the Vegetable-sheep (Raoulia eximia) association 
of low rock, even with the surface or slighly raised above the desert of shingle- 
slip, at an altitude of from 1200—1800 m and upwards. The great cushions, 
already described, frequently grow into one another, forming hard, white, amor- 
phous masses 2m in length, or mofe. Thanks to the wet raw humus within, 
 colonies of Celmisia spectabilis, C. viscosa, Aciphylla Colensoi and Danthonia 
flavescens grow as epiphytes on the cushions, being quite independent of 
the rock. The station, fully exposed to sun and wind and subject to great 
daily extremes of temperature at all seasons, except when buried beneath the 
snow in winter, is one of extreme xerophily. 
The Olearia insignis association, already described for the coast and the 
_ lowlands, ascends to about an altitude of goo m, clothing the cliffs of river 
valleys of the North-eastern district. As a higher altitude the Olearia, nn i 
a but. eh Atanr on; SRSERER to 1500 m, or more. ; 
1) On en rocks i u river gorges of the Inland Kaikoura Mts. the shrub may be as u 
R ai with. pn rosettes er. to the rock. and far-penetrating thiek root are local s 
Dessen re the North-western, the North-eastern and Eastern distriets vespestieh 
0 extends into o the laden distriet i in the Mount area. 5 
